Explosive priming composition



United States Patent Dfiice 3,131,102 Patented Apr. 28, 1964 3,131,102 EXPLGSWE PREMKNG CQMPSSHTION Joseph F. Kenney, Bridgeport, Conn, assignor to Remington Arms Company, Inc., Bridgeport, Comm, a corporation of Delaware No Drawing. Filed Apr. 5, 1962, Ser. No. 185,188 2 Claims. (Cl. 149-78) This invention rel-ates to a percussion priming composition for ammunition and like explosive devices which is characterized by a high degree of sensitivity and stability even when exposed for considerable periods of time to abnormally temperatures.

A possible use for such mixtures is in connection with explosively powered release devices adapted for use with missiles and high speed air or space craft which may be subject to relatively high degrees of frictional heating.

Some conventional primers will explode when subjected to high temperatures and others will decompose to such an extent they will no longer be sufficiently sensitive to be ignited by the conventional percussion device.

This invention results from the discovery that tetranitro ('libenzo 1,3a,4,6a tetraazapentalene, is a high explosive having unusual stability when exposed to high temperatures and that this substance, usually known as TACOT, can be used as an ingredient in a percussion priming mixture without tending to reduce the sensitivity or thermal stability of the other components of the mixture. As a high explosive, TACOT makes an important contribution to the explosive efiiciency and powder igniting characteristics of the mixture.

An exemplary priming mixture according to tionmay be composed as follows:

the inven- Preferred, percent Limits, percent Such a mixture when tested in Remington #72 primers showed a drop test sensitivity of X 8.04" with a standard deviation of 1.38". These figures were obtained using a 4 ounce weight. Although the values are somewhat high, a widely used commercial priming composition has a drop test sensitivity of Y 4" so that primers made in accordance with the invention are well within the useable range. Such a mixture has been proven to remain stable and sensitive when exposed to temperatures of 400 F. for at least 1,300 hours as compared to 4 to 8 hours at 350 F. for the commercial mixture referred to above.

It will be noted that but for the addition of TACOT this mixture is a substantially conventional pyrotechnic type mixture depending primarily upon the unusually active nature of the oxidizing agent to combine with reasonably active fuels under the action of percussion. TACOT within the limits referred to does not materially reduce sensitivity and does not reduce the stability of the mixture. TACOT does contribute substantially to the explosive and igniting power. The use of TACOT in substantially high proportions should be avoided unless somewhat reduced percussion sensitivity can be tolerated, for TACOT is a relatively soft flufty substance tending, when present in substantial quantity, to reduce the eifect of percussion means in igniting the mixture.

TACOT itself is an invention of others, a tetranitro compound of dibenzo 1,3a,4,6a-tetraazapentalene (Reissue Patent No. 25,238 to Rudolph A. Carboni) formerly known as dibenzo 1,2,5,6 tetraazacycloteoaene (Patent No. 2,904,544 to Rudolph A. Carboni), broadly covered by the Carboni patent and its reissue, and in pending applications, :all assigned to E. I. du Pont de Nemours and Company.

TACOT is identified by its commercial producer E. I. du Pont de Nemours & Company, Inc., as tetranitrodibenzo 1,3a,4,6a-tetraazacyclotetaene, C H N O a high explosive having approximately 96% of the explosive power of TNT, molecular weight of 388.212, melting point 378 C. (710 F.) and orange to red in color.

Accordingly I do not claim TACOT itself and intend that my claims should be limited to particular mixtures in which TACOT is the principal explosive ingredient combined with oxidizers and -fiuels which by themselves are not explosive substances.

1 claim:

1. A priming mixture consisting of the following materials:

Percent Potassium chlorate 45 to 58 Antimony sulfide 15 to 35 Calcium silicide 2 to 22 Tetranitrodibenzo-1,3a,4,6a tetraazapentalene..- 2to 10 2. A priming mixture consisting of the following ingred-ients:

References Cited in the file of this patent UNITED STATES PATENTS 1,308,394 Buell July 1, 1919 1,447,551 Henning Mar. 6, 1923 1,473,818 Henning Nov. 13, 1923 

1. A PRIMING MIXTURE CONSISTING OF THE FOLLOWING MATERIALS: PERCENT POTASSIUM 45 TO 58 ANTIMONY SULFIDE 15 TO 35 CALCIUM SILICIDE 2 TO 22 TETRANITRODIBENZO-1,3A,4,6A TETRAAZAPENTALENE 2 TO 10 